200NC Discharge Curve?

Discussion about the OutBack Energy Cell Batteries
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jacobtuft
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Posts: 1
Joined: Sun Oct 20, 2019 10:29 pm

200NC Discharge Curve?

Post by jacobtuft » Sun Oct 20, 2019 10:34 pm

Hi All,

I'm having a terrible time finding the discharge curves for the 200NC battery. The one that shows voltage vs state of charge.

I'm trying to figure out what voltage corresponds to 60% SOC so I know when I need to start the generator.

Thanks.

-Jacob

raysun
Forum Emperor
Posts: 1011
Joined: Tue Jul 26, 2016 5:57 am
My RE system: Flexpower One: FX3048T, (2) FM80, MATE3s, FlexNetDC
Outback 200NC batteries (8 @ 48v)
Outback IBR3 battery enclosure
Suniva 330 watt panels (12 - 6 Strings @ 2 Series)
Hyundai 355 watt panels (6 - 3 strings @ 2 series)

Re: 200NC Discharge Curve?

Post by raysun » Mon Oct 21, 2019 8:40 am

I use 200NC and find the discharge curve fairly typical of AGM lead acid batteries. However, voltage v.s. SOC is a tricky proposition as it varies with load. In order to measure it with any accuracy, the battery must be in an open-circuit state (no load) for at least several hours, with 24 hours needed to assure a high degree of stability for the reading.

For example, under load, my 48V @ 350AH battery is at 65% SOC. With ~ 8A draw = 48.5V. With ~ 25A draw = 48.0V.

Most systems in continuous use (like my off-grid system) are best monitored using a "coulomb counter" that measures charge into and out of the battery to derive SOC. Outback's meter for this is the FlexNET DC. There are other quality counters as well.

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